Actuation systems are used in aircraft to drive various control surfaces such as the leading edge flap of a power drive unit. Most often, dual redundant load paths are required for safety purposes to allow continued operation of the power drive unit in the event of a single point failure outside the driving motor. In other words, the motor is part of a power drive unit which drives the leading edge flap through a dual load path to a set of actuators. If a failure occurs in one of the load paths, the other load path still is operative to allow driving the leading edge flap.
Heretofore, many configurations of dual redundant load path systems have been proposed to satisfy this need and/or requirement. Typically, a single motor output, such as a single motor shaft, operates the system by driving dual redundant shafting and gearing paths. However, such configurations are vulnerable to a single point failure at the output of the motor shaft itself This would free the control surface and create possible safety problems in flight conditions.
This invention is directed to solving such problems, and particularly to the problem of single point failure at the output of the motor shaft in dual redundant load path systems.